Weather warnings for rain have been extended to parts of the West of Scotland as forecasters warned “summer was over”.
A yellow alert will remain in force throughout Saturday as up to four inches of rain could fall within a matter of hours.
The Old Firm clash between Celtic and Rangers at Parkhead is likely to be played out against a dreich backdrop after months of sweltering temperatures.
Downpours are also expected in the south west, where the alert is to remain in place from midnight until 11.59pm, but further inclement conditions are expected into Sunday.
STV weather presenter Philip Petrie warned it was likely to be “unsettled and considerably wetter and windier than the past few days” over the course of the weekend.
He added: “For much of this week our weather has been dominated by high pressure, but over the next 24 hours we will see the replacement of that high with a large area of low pressure. High pressure = good weather, low pressure = bad weather.
“Unfortunately we will see a continuation of several bands of heavy rain spiralling around the low pressure, meaning that over the weekend for central and southern areas in particular, we will have constant bands of rain.”
An initial yellow alert only covered parts of Ayrshire and Dumfries and Galloway, but this has now been extended further up the coast.
Parts of Northern Ireland are also set to bear the brunt, Met Office forecasters warned.
“Areas of heavy rain are expected to pulse northwards across much of Northern Ireland and the south west of Scotland through Saturday, potentially accompanied by thunderstorms,” meteorologists said.
“Rainfall totals of 30 to 40mm could fall in two to three hours in some places with a small chance of 80 to 100 mm in 24 hours.
“These higher totals are more likely for western Scotland whilst for Northern Ireland 40 to 50mm is more likely. This may bring localised flooding and travel disruption.”